A 3-D Backstripping Method and Its Application to the Eromanga Basin In Central and Eastern Australia

Abstract

S U M M A R YA general 3-D backstripping method, based on a precise model of plate deformation, is developed for analysis of the tectonic history of sedimentary basins, and it has been applied to the Eromanga Basin in central and eastern Australia. The 3-D method is more appropriate when dealing with the subsidence history of basins, since it takes into account both the flexural effect of surface load and the stress relaxation in the lithosphere due to viscous creep of mantle material. Furthermore, this method is more accurate than conventional thin plate models. It is shown that the 3-D model provides a different, yet simple and clear evolving picture of the areal extent of the tectonic subsidence of basins.The 3-D analysis results show that the formation of the Eromanga Basin is characterized by a gradual increase in the extent of sedimentation with localized subsidence from the Late Triassic to the Early Cretaceous and a large extension of sedimentation with rapid subsidence during the Early to Middle Cretaceous, followed by local and gradual subsidence after the Middle Cretaceous.